Fluorescence imaging of single molecules in polymer microspheres

Area of Science:

• Polymer Science
• Optical Physics
• Nanotechnology

Background:

• Far-field fluorescence imaging is crucial for observing nanoscale phenomena.
• Single molecule studies require stable fluorescence signals to avoid photobleaching.
• Polymer microparticles offer unique environments for molecular studies.

Purpose of the Study:

• To investigate single molecule fluorescence imaging within polymer microparticles.
• To compare photobleaching properties of rhodamine 6G in different polymer matrices.
• To explore the potential of theoretical calculations for image analysis.

Main Methods:

• Microdroplet techniques for producing spherical polymer microparticles.
• Far-field fluorescence microscopy for single molecule imaging.
• Photobleaching quantum yield measurements of rhodamine 6G.
• Semiclassical electrodynamics for image calculation.

Main Results:

• Significantly lower fluorescence photobleaching quantum yields (at least five times smaller) for rhodamine 6G in polyvinyl alcohol compared to ethanolic solvents.
• Larger average fluorescence signals from single molecules in polyvinyl alcohol microspheres.
• Acquisition of multiple images from a single molecule over several minutes.
• Successful calculation of fluorescent images from semiclassical electrodynamics.

Conclusions:

• Polyvinyl alcohol microparticles provide a superior matrix for single molecule fluorescence imaging due to reduced photobleaching.
• Extended observation times are achievable, enhancing the study of single molecule dynamics.
• Theoretical modeling can aid in interpreting experimental fluorescence images.